My point was this, that it is not very difficult, and it is courteous, to at least find out the name, and therefore the gender, of the CP that you are applying to. Being part of a mail-shot of "Dear Sir's" isn't as impressive as getting a resume from someone who has done the research into your company, and at least knows what sort of aircraft you operate and what sort of ops you are involved in.
For example, if you get to talk to the CP and they say "Why do you want to work for our company?" which is better.
" I just want a job with any company" or
"Because I would like to specialise in the areas you specialise in such as....and I like the way you run your operations such as...."
When looking for a job in any competitive industry, an applicant needs to have an edge over the others. Most of us will have a few people that we already know and have seen doing good work, in mind for the next position that comes up. So be one of those people!
If a hapless poor-sod applicant has to send a hundred letters, then they have missed an important part of their training, that in this and many other industries, it is the network of people you have got to know so far, and the impression that you have made on those people, that really counts.